Thermally actuated sprayer



Patented July 10, 1951 UNITED STATES PATENT OFFICE THERMALLY ACTUATED SPRAYER John T. Efford, StratfordL, Conn., assignor to Bridgeport Brass Company, Bridgeport, Conn.,

a corporation of Connecticut Application January 31, 1950, Serial No. 141,530

This invention relates to a thermally actuated sprayer of the type furnished the ultimate user in the form of a container hermetically sealing a normally liquid spray material. This container has a spray outlet sealed so that when the container is heated to vaporize or boil the spray material the seal fuses and the spray is ejected by the internal pressure.

Such a type is believed new and is disclosed and claimed in the John T. E'fford patent application filed May 1, 1943, Ser. No. 24,463. The present application continues in part this earlier application and includes a new disclosure pertaining to an improvement aimed at providing a lower cost form of the described type of sprayer.

The above outlines the primary object of the present invention, namely, to produce at minimum cost a sprayer of the thermal type. Another object is to attain this low cost objective while producing an eifective spray having aerosol characteristics similar to those developed by a sprayer of the type comprising a container having a manually controlled valve and otherwise hermetically sealing a liquefied gas under pressure. This last mentioned type requires a container capable of resisting the pressure required to maintain the gas liquid. The type with which the present invention is concerned requires a 1 Claim. (01. 22254) gitudinally and the can container only strong enough to resist. the pres- 7 sure developed when the spray material is vaporized by heating. During this time the spray is continuously ejected so that there is a continuous pressure loss.

A specific example of a thermally actuated sprayer is disclosed hereinbelow with the aid of the accompanying drawings. This is for the purpose of explaining the principles and operation of the various features of the present invention. These features may be incorporated in other forms once they are understood.

In these drawings- .Fig. 1 is a side elevation with the lower right hand portion in section to reveal the internal construction; 7

Fig. 2 is an end view of Fig. l; and

Fig. 3 isa top view of Fig. 1.

In this specific example the container 1 is in the form of a tin can of the type known in the tin can industry as a packers sanitary can. Thus the sheet steel from which the can is made is of 29 gauge maximum and preferably a somewhat lighter gauge. It may be tinned by either hot dipping or electrolytic methods, the latter being preferred. The can body has the characteristic soldered side seam 2 extending lonstructible seal 6. I temperature melting solder or a thermoplastic. The innerend of the tube may be ends 3 are characteristically flat and are attached to the body by the characteristic rubber or plastic sealed double.

seams t.

This can contains and hermetically seals therein a normally liquid spray material to provide a package. The can may be filled and the top can end applied by the same type of equipment that food packers use. Cans of this type may :be obtained with their insides lacquered with different types of lacquer which are normally can ends 3 through a suitable hole formed for Solder may be used to hermet ically seal the tube inthe can end. This tube extends diagonally through the can end ata. location relatively adjacent but spaced somewhat from the can periphery so that the inner this purpose.

tube end is adjacent, close to or practically in contact with the inside of the can body. This inner tube end is closed by a thermally de- This seal may be either a low material. dipped into the material so that a sheath is formed around its end. As illustrated, the outside of this seal 6 actually contacts the inside of the can body. The inner tube end is shown close to but not quite reaching the longitudinal center of the can. The outside portion of the tube may be kept short as illustrated.

Preferably thetube 5 extends through the top I of the can because this facilitates packing of the liquid spray material. Its point of passage through the can end may be sufiiciently far from the seam 4 to avoid interfering with the application of the can end to the can body.

A feature of the invention is that the inner: end of the tube 5 with its seal 6 is located remote" from the soldered seam '2. As shown'by Fig. 1", the arrangement may be such that the thermally 6 the heat used to heat the spray material and the seal 6 does not heat the seam 2 above the fusion temperature of the solder that maintains the seam tight and hermetic.

The illustrated sprayer package includes a stand or support that is connected with the can I to form a self-contained unit. This stand is shown as being made. from two lengths of wire, each length being looped tightly around one extreme end of the can as at I and then extended radially from the can body in a radial plane aligned with the inner tube end and the seal 6' and then looped at right angles asiatfl to form. a base or bases. This wire stand may have the wire ends interfastened by solder orthe wire may. be intertwisted as at 9 to form a purely mechani cal connection. One of the wire lengths is looped upwardly from a base portion flandprovided with a pan III which may be a sheet steel stamping. This pan is proportioned to receive a lump or piece of solidified fuel. Illa such as solidified alcohol'. or a hydrocarbon" gel.

With the illustrated sprayer package resting; on a flat support by way' of'itsbase portions 8; the can I is horizontally positioned with the tube diagonally pointing upwardly. The can I may be the standard twelve ounce packers sanitary can. A suitable spray material. is. methylene chloride which is: normally liquid and which includes a DDT and pyrethrum mixture or tetraethylpyrophosphate. With this type of materiaL,

an. inside diameter of. .025 is suitable for the tube. 5'.

The inside of the can I andlthe portion of the tube, 5 that. contact the spray mixture may be protected. by a coating that does. not react with the spray material; This may be necessary ifa material is used which mightcause trouble by its contacting the tin., In some instances, thisprecaution may proveunnecessary.

.With. some spray materials, the low melting temperature solders, have theirnormal melting. temperatures increased. abnormally by reaction with .the materials. Insuchinstancesthe solder shouldbe. protected from thematerial by a suit.- able coating Preferably one of. the. various presently available. thermoplastic materials. is used=for the seal 6 in-the case ofsuch'spray. materials.

Thepan. I0 is-preferably proportionedtahold the solidifiedf-uel Illa in a size suitable for heat.- ing the material, just high enough to keep. the. spray material boiling during the operation of the. device. The seal 6, may be provided with; a. destruction temperature approximately coin: cidingr with-.thetemperature'of the spray. material, required for the. development of properspraying. pressure.

Upon igniting thepiece of solidified fuel Ill, the spray materialstartsto heat. In-the case of methylenachloride, atemperature of aboutl809 F. develops. the properpressure and in, that instance the seal-6 should be of. a compositionthatmeltsor softens'adequately toblow out ataboutthis temperature. As heating. starts, theround. shapezof thecanpermits convection currents of the-spray material: to agitate the spray material to: tend to; prevent premature destruction. of theses-L61 'I-heseal Iifuseswhen the-contents of the can; are,- practically uniformly: heated to about 18D F. in the case of the exemplary materials. The: outside of. the can I immediately above the fuel. Illa may rise above the softening temperaturevof. the. solder used. by can manufacturers in making; ordinary sanitary. cans. An important advantage is that this does not cause trouble at '4 v the soldered seam 2 because the latter is well away from this zone of localized temperature.

Just about as the material reaches F. or shortly therebefore, the seal 6 softens so that the internal pressure can drive the spray material through it and out the tube 5. The small diameter of the tube 5 in conjunction with its length creates a spray: having aerosol characteristics if not oftrue aerosol" nature. Any'particles of the seal that are blown up through the tube 5 are positively kept soft and fluid or plastic so the pressure How can continue. The tube is immersed in the hot spray material throughout most of" its length, its short outside end being kept hotbyconduction.

Due to the fact that the entire sprayer package can be: made so.-economically, the device may be discarded after being used once. Other than for the small diameter tube 5, the production cost of the package is little more than that connected with-anyother canned product. The-tubeliszrelatively inexpensive. With most practical spray: materials, a- .025 insidediameter is suitable when. the length of the tube-E-is about Zlinches. The tube. need not be seamless but maybe any small sizedi tube. When the ihsidediameter is smallit'is DOS-- sible to obtaina true aerosol or to closely approach. such a dispersion. In the interest of economy thetube may bemade as short as is consistent'with obtaining the desired spray.

The spray material maybe-anynormally-liquid material and this liquid material may contain or carry various types of active=ingredients de'- pending on the purpose for' which thesprayer package is intended; The material suggested issuitable as a general insecticide; The important thing isthat the present inventionprovides fora very inexpensive thermally actuated sprayerpackage whichcan be produced by thosefamiiiar' with canning procedures and which represents a practical and substantially foolproof" device:

In some instances it'may be preferable to posi'-- tively fix the wire loops orloops I non-rotati'velyto the can-body I by-spots of solder. The-location of the soldering points is relatively immaterial in this instance because, when the device is in operation, it will not matter if the solder-letsgo, since there will beno chancefor-thecan I to turn when-inuseand standing'stationary: The tube 5 is' illustrated as being made ofmetal and installed in the; can end by the use of solder: This is an inexpensive and' practicalway to install it.

It is to be understood. that the fiat carrends are applied mechanically with a soft materialsuch as rubber or a plastic providing" gaskets for fluide-tightness; The can manufacturer provides cans. with one end applied. to each and a sumcientnumber of'en'd's to, close the other end of each, Machinery is available for automatically filling the cansandapplying the can ends;

The can may, also be made. from tin-mill black plate with a suitable coating other than. tin preventing possible reaction. between the steel and the contents of thev can and rusting of'the cans outside. The. can material; may beany, metal; of adequate low cost. comparable. to the" materials sug ested.

Iclaim:

A spray package including a can havinga cylindrical body wall and fiat end; walls, said. body wall having a longitudinally extending seam sealed. with solder, a substantially straight metal tube passed. diagonally. throughv one of said end Walls at a location spaced from said" walls peterial inside of and fluid tightly enclosed by said can and adapted to vaporize when heated, and a stand connected with said can and adapted to support it horizontally with the portion of said body adjacent said inlet end and said seal down- 10 Number wardly and with said stand having a fuel piece support positioned below said portion.

JOHN T. EFFORD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date 2,244,302 Lynn et al. June 3, 1941 

